The present invention relates to a movable object position detecting apparatus for detecting a position of a movable object running in a fixed field, more specifically to a movable object position detecting apparatus for use in a race game in which movable objects, such as model horses, model cars or others, run a race in a fixed field.
Conventionally there are many kinds of race game devices for games imitating horseraces, car races, etc. In conventional race game devices, movable objects, e.g., model horses, model cars, etc. run on circulatory tracks to compete places or anticipate places. In these race games, however, the movable objects can run only fixed circulatory tracks, which unavoidably reduces actual-site feeling and makes the games much less interesting.
The assignee of the present application filed a Japanese patent application (Japanese Patent Laid-Open Publication No. Sho 63-094884/1988) on an epoch-making race game device in which a race can be competed by free run on a field in place of run along a fixed course on the field. In this race game device, since movable bodies, such as model horses or others can run freely on a field, it is possible to develop a race in which, as in an actual horserace, tricks of running model horses, running a shortest distance, interfering with runs of other model horses, and other techniques are used. Accordingly the race game device can provide race games having actual-site feeling, and is very popular.
In this race game device it is necessary to constantly detect a position of a movable body, and to run the movable body smoothly at a speed which is above a certain speed, it is necessary to detect a current position at a frequency above certain frequency. This has put a limit to a number of movable bodies which are run at once. For example, to detect a position of a movable body above 50 times a second, the currently used race game devices allow only about 6 movable objects to run at one once and cannot meet a desire that a larger number of movable objects would be run at once.